Filter, Composition and Process for Cleaning Feed and Exhaust Fluids and Method for Eliminating PFAS and other Noxious Impurities in Fluids

ABSTRACT

A fluid filter, filtering medium composition, and associated process for removing contaminants from feed and exhaust fluids used in fuel cell electricity generation, laboratories, the semiconductor and other industries to improve performance and extend useful equipment lifetimes and to clean fluids of sulfur compound contaminants, as well as to remove noxious NOx and halogen contaminants from feed and exhaust gases.

CROSS REFERENCE TO RELATED APPLICATIONS

This application claims priority to U.S. Pat. Application 17/676,443,filed on Feb. 21, 2022, and thereby to Provisional Patent Application63/226,077, filed on Jul. 27, 2021, each incorporated herein byreference.

STATEMENT REGARDING FEDERALLY SPONSORED RESEARCH OR DEVELOPMENT

No federal government funds were used in researching or developing thisinvention.

NAMES OF PARTIES TO A JOINT RESEARCH AGREEMENT

Not applicable.

SEQUENCE LISTING INCLUDED AND INCORPORATED BY REFERENCE HEREIN

Not applicable.

BACKGROUND Field of the Invention

The invention is a filter composition and associated method forpurifying feed gases and liquids used for fuel cells, laboratories, thesemiconductor, and other industries to improve performance and extenduseful equipment lifetimes, as well as eliminating sulfur compounds fromother fluids, and to remove noxious contaminants from exhaust gases andliquids. Hydrogen sulfide (H2S), sulfur containing hydrocarbons known asmercaptans or thiols, sulfur containing compounds such as carbonylsulfide, carbon disulfide, and so on, as well as Per- andPolyfluorinated substances (PFAS), including Perfluorooctane sulfonate(PFOS) and Perfluorooctanoic acid (PFOA),are the most common, and mostdifficult to remove, of the contaminants that poison the catalysts usedin fuel cells to generate electricity, the catalysts and chemicals usedin laboratory and industrial applications such as petroleum refining,the semiconductor industry, and many others.

Background of the Invention

Sulfur containing contaminants in concentrations of even parts perbillion can cause failure of equipment that should last many years injust a few years or, in extreme cases, in months. Inexpensive filteragents, such as activated carbon and common metal oxides, can lower theconcentration of these sulfur containing contaminants, but cannot removethem to the extremely low levels required for optimal performance andlifespan in these specialized industries. “Sour gas” is known as naturalgas or any other gas containing significant amounts of H₂S or othersulfur containing compounds that can be damaging to pipelines,equipment, and be unpleasant to smell. Before a raw natural gascontaining sour contaminants can be used, the raw gas must be treated toremove those impurities down to acceptable levels commonly by an aminetreatment process conducted within oil and natural gas refineries. Theremoval of hydrogen sulfide and other organosulfur compounds is referredto as “sweetening”. The sweetened products lacks the sour, foul odors ofthe organosulfur compounds, but this “sweetened” product is notcompletely free of organosulfur compounds.

Per- and Polyfluorinated substances (PFAS), including Perfluorooctanesulfonate (PFOS) and Perfluorooctanoic acid (PFOA), are contaminantsbelieved to cause multiple adverse health effects in humans, includingincreased cancer risk, decreased fertility, interference with the immuneand endocrine systems and childhood development. Energy companies areknown to have used PFAS and/or substances that can degrade into PFAS inhydraulic fracturing (“fracking”) in hundreds of U.S. wells. Thepresence of PFAS in industrial fluids can lead to contamination ofadjacent water sources. Known industrial and commercial filters such asactivated carbon do not reliably remove PFAS, which requires reverseosmosis to be removed from water. PFAS are known as “forever chemicals”that do not break down due to fluorine’s electronegativity and chemicalstability.

The use of absorbents and adsorbents consisting of oxides of metallicelements to remove sulfur from sour gas is known. See, e.g., U.S.5,853,681 to Denny et al. and U.S. 8,596,407 to Hatscher.

What is needed is a simple, efficient and cost-effective method ofremoving hydrogen sulfide, organosulfur, chlorine and other halogens,nitrous oxides, PFAS, and other contaminants to very low levels fromfluid streams intended for use in fuel cells, other sulfur andcontaminant sensitive industrial and laboratory applications, inorganicliquids and various organic liquids.

BRIEF SUMMARY OF THE INVENTION

In a preferred embodiment, a fluid filter for attachment to a gas orliquid line, such fluid filter comprising a housing packed with afiltering medium composition of granular particles ranging in size fromabout 15 mm to about 0.001 mm and consisting of a homogeneouscomposition of oxides of aluminum, antimony, barium, beryllium, bismuth,boron, cadmium, calcium, cerium, cesium, chromium, cobalt, copper,dysprosium, erbium, europium, gadolinium, gallium, germanium, hafnium,holmium, indium, iron, lanthanum, lead, lithium, lutetium, magnesium,manganese, molybdenum, neodymium, nickel, praseodymium, rhenium,rhodium, samarium, silicon, silver, strontium, titanium, vanadium,ytterbium, yttrium, zinc and zirconium, further comprising elementalgold, palladium, and platinum collectively comprising between 0.000001%and 0.002% of the filtering medium.

In another preferred embodiment, the fluid filter as described herein,further comprising an input line, wherein the housing has a diameterthree or more times larger than the input line diameter.

In another preferred embodiment, the fluid filter as described herein,wherein the housing is three or more times longer than its own diameter.

In another preferred embodiment, the fluid filter as described herein,wherein the granular particles range in size from 4 mm to 0.04 mm.

In another preferred embodiment, the fluid filter as described herein,wherein the filter medium composition is at least 80% oxides of copperas determined by ICP-MS solution analysis of nitric acid digestions ofthe medium.

In another preferred embodiment, the fluid filter as described herein,wherein the filtering medium is comprised of at least 90% by totalweight oxides of copper.

In another preferred embodiment, the fluid filter as described herein,further comprising a contact temperature range from ambient temperatureup to 500° C.

In another preferred embodiment, the fluid filter as described herein,wherein the contact temperature ranges from 30° C. to 300° C.

In another preferred embodiment, the fluid filter as described herein,wherein the composition of the filtering medium composition isrecyclable or regenerable.

In another preferred embodiment, a filtering medium composition ofgranular particles ranging in size from about 15 mm down to about 0.001mm and consisting of a homogeneous composition of the oxides ofaluminum, antimony, barium, beryllium, bismuth, boron, cadmium, calcium,cerium, cesium, chromium, cobalt, copper, dysprosium, erbium, europium,gadolinium, gallium, germanium, hafnium, holmium, indium, iron,lanthanum, lead, lithium, lutetium, magnesium, manganese, molybdenum,neodymium, nickel, praseodymium, rhenium, rhodium, samarium, silicon,silver, strontium, titanium, vanadium, ytterbium, yttrium, zinc andzirconium plus elemental gold, palladium, and platinum, whereinpercentages of components are given by total weight and: oxides ofcopper comprise at least 80% of the filtering medium, non-copper oxidescomprise between 0.001% and 19.9999% of the filtering medium, andelemental gold, palladium and platinum comprise between 0.000001% and0.002% of the filtering medium.

In another preferred embodiment, the filtering medium as describedherein, wherein: oxides of copper comprise up to 90% of the filteringmedium, non-copper oxides comprise between 0.001% and 9.9999% of thefiltering medium, and elemental gold, palladium and platinum comprisebetween 0.00001% and 0.0001% of the filtering medium.

In another preferred embodiment, a process for removing hydrogensulfide, sulfur containing compounds such as thiols or mercaptans,oxides of nitrogen, PFAS substances and halogens from a gas or liquidstream that lowers the concentration of these contaminants to levelsthat are below the limit of detection of standard laboratoryinstrumentation by passing the gas or liquid stream through a fluidfilter, such filter comprising a filter housing with a contacttemperature ranging from about ambient to about 500° C. that is packedwith filtering medium composition of granular particles ranging in sizefrom about 15 mm down to about 0.01 mm and consisting of a homogeneouscomposition of the oxides of aluminum, antimony, barium, beryllium,bismuth, boron, cadmium, calcium, cerium, cesium, chromium, cobalt,copper, dysprosium, erbium, europium, gadolinium, gallium, germanium,hafnium, holmium, indium, iron, lanthanum, lead, lithium, lutetium,magnesium, manganese, molybdenum, neodymium, nickel, praseodymium,rhenium, rhodium, samarium, silicon, silver, strontium, titanium,vanadium, ytterbium, yttrium, zinc and zirconium, further comprisingelemental gold, palladium, and platinum collectively comprising between0.000001% and 0.002% of the filtering medium.

In another preferred embodiment, the process as described herein,wherein the stream flows upward through the filter.

In another preferred embodiment, the process as described herein,wherein the fluid filter is the fluid filter previously describedherein.

In another preferred embodiment, the process as described herein,wherein the filtering medium is the filtering medium previouslydescribed herein.

In another preferred embodiment, the process as described herein,wherein the stream is comprised of hydrogen, natural gas, biogas, orother laboratory or industrial gases or mixture of gases comprising airand specialty high purity composite gases of the grade known as“Chemically Pure” or “Research” that are bottled gases typicallyavailable to laboratory and industrial customers, in pipelines, inexhaust streams, or of liquids such as organic or inorganic liquids.

In another preferred embodiment, the process as described herein,wherein hydrogen sulfide, thiols, mercaptans, other sulfur containingmolecules, oxides of nitrogen, PFAS substances and halogens are removedfrom feed or exhaust fluids.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 is a line drawing evidencing a filter as used in the inventiveprocess.

FIG. 2 is a graph evidencing results of the inventive filter in anatural gas flow.

DETAILED DESCRIPTION OF THE INVENTION

The disclosed filter composition and associated method addresses theproblem of sulfur, PFAS, halogens, and other contaminants contained influids, and noxious nitrous oxides in feed and exhaust gases, byproviding a means and method for removing such contaminants. For thepurposes hereof, the word “fluid” will mean both gases and liquids.These contaminants in fluids can rapidly degrade and damage theperformance of specialized catalysts and instrumentation, make wellwater smell and taste bad, and contaminants in exhaust gases are harmfulto human health and to the environment. Independent studies demonstratethat sulfur-containing compounds contained in hydrogen and other fueland feed gases can be reduced to levels that are undetectable bysophisticated instrumentation.

An inventive method to purify a gas stream consisting of hydrogen,natural gas, biogas, or other gasses, or a fluid stream of an organic orinorganic liquid must involve removing hydrogen sulfide, organosulfurcompounds, PFAS, halogens, and other noxious impurities such as nitrousoxides from gas streams to the lowest concentration possible by passingthe stream through a filter housing, wherein such housing is packed witha filtering medium comprising a composition of granular particlesranging in size from about 15 mm down to about 0.01 mm and consisting ofa homogeneous composition of the oxides of aluminum, antimony, barium,beryllium, bismuth, boron, cadmium, calcium, cerium, cesium, chromium,cobalt, copper, dysprosium, erbium, europium, gadolinium, gallium,germanium, hafnium, holmium, indium, iron, lanthanum, lead, lithium,lutetium, magnesium, manganese, molybdenum, neodymium, nickel,praseodymium, rhenium, rhodium, samarium, silicon, silver, strontium,titanium, vanadium, ytterbium, yttrium, zinc and zirconium plus tracesof elemental gold, palladium, and platinum. In a primary embodiment, theelemental gold, palladium, and platinum only collectively comprisebetween 0.000001% and 0.002% of the filtering medium.

The distribution of sizes of the particles within the filter housing isdependent on the diameter of the housing, the flow rate, the gaspressure, and the permitted pressure drop passing through the filter.Very small housings of the laboratory type would contain only very smallparticles ranging from about 10 to about 150 microns while a largeindustrial type filter housing would typically contain particles rangingfrom about 50 microns up to about 5 mm or more.

Copper is the principle metallic component of the granular filteringmedium thus, in one embodiment of the inventive filtering medium, theoxides of copper comprise up to approximately 90% of the composition bytotal weight. In another embodiment, copper oxides may comprise aslittle as 80% as determined by either total weight or ICP-MS solutionanalysis of nitric acid digestions of the medium. However, due to thepresence of the non-copper metal oxides and the three metals in thecomposition, the composition does not behave like pure copper oxide,which would react to become copper metal and H₂O in the presence ofhydrogen, natural gas, or biogas. The other metallic oxides can be asmuch as 20% of the composition. The three elemental metals of gold,palladium and platinum are present in very small amounts, only up toabout 0.002%, for example.

The filtering medium composition is created as a homogenous mixture witha broad range of grain sizes to reduce potential open spaces and, thus,media bypass during the filtering process. Once the medium is createdand mixed to ensure uniformity, it is then inserted into the filterhousing.

To create the inventive granular filtering medium, a solution containingthe soluble compounds of copper with the other metals in proportions oftotal weight ranging from 0.0001% up to 1% is contacted with a 20%solution of sodium hydroxide in water to form a homogeneous precipitateof hydroxides of the metals which are then dried and heated to drive offthe water of hydration. This process produces a mass of homogeneoussolid material that is then broken into irregular granules with a jawcrusher followed by sorting the broken sizes with a rotary screeningmachine comprising a connected series of rotary sieves arranged as acolumn. In a preferred embodiment, the column comprises two sieves. Thevery fine particles pass all the way through the column of sieves andare used for the very small diameter filters, or are aglomerated intosemi-spherical pieces, the particles that pass through the upper sievebut not through the bottom sieve are used in the medium diameter sizedfilters, and the largest particles that do not go through the uppersieve are used for large filter housings or are recycled back to thecrusher for additional size reduction. With this arrangement, a broadbut a controlled range of particles are available for packing the filterhousing. The result is that little to none of the particles are wasted.

In a preferred embodiment, the housing of the filter will becylindrical, made of materials resistant to attack from the fluid beingfiltered, and the filtering medium will be contained within the housingto prevent migration of the medium past the filter.

The filter housing can be composed of anything that will resist thepressure, temperature, and attack of the fluid being filtered, such asstainless steel, aluminum, other known corrosion resitant alloys, carbonfiber, compositions such as plastic or fiberglass when operated atsuitable low temperatures and pressures, and so on.

The disclosed filter will be embodied to filter hot oxygen free gases,allowing filtration of any oxygen free gas between ambient airtemperature up to about 500° C., or gases containing oxygen attemperatures between ambient up to about 120° C., or liquids withoutlosing efficiency or degrading the filtering medium composition ofgranular particles.

The medium within the filter housing can be recycled, regenerated, ordisposed of depending on the use of the filter. The useful lifetime ofthe filter is dependent upon the concentration of the contaminant in thefluid stream being filtered. The filtering medium will typicallyincrease in weight by about 20% due to the sulfur and other impuritiesit has trapped. A filter housing containing 1,000 grams of filteringmedium can absorb approximately 400 grams of H2S or more, which is theequivalent of approximately 300,000,000 Liters of 1 ppm H2S atatmospheric pressure and ambient temperature.

In a preferred embodiment, the housing will have a diameter of three ormore times the diameter of the input line to spread and slow the flowthrough the filtering medium to decrease the pressure drop created bythe resistance of the flow through the medium, and have a length ofthree or more times its own diameter to insure adequate contact betweenthe fluid being filtered and the filtering medium. Also preferably, thefilter housing will be arranged such that the feed will flow upwardwithin the body of the housing in order to prevent packing of the filtermedium that would increase the pressure drop within the housing.

Laboratory testing of the inventive filter has consistently yieldedpositive results. In a first lab test, 108 ppb of H2S contained in a99.99% hydrogen sample was reduced to below 6 ppb, the limit ofdetection, by passing the gas through the inventive filter. In anotherlab test, 1.902 ppm H2S passed through the inventive filter and yieldeda concentration of H2S below the limit of detection of 200 ppt. In athird test, both low and high concentrations of H2S, carbonyl sulfide,dimethyl disulfide, methyl mercaptan, and thiopene were passed throughthe inventive filter and testing of the filtered gas could not detectany of these sulfur containing compounds.

Detailed Description of the Figures

Turning now to the figures, FIG. 1 shows the inventive filter 10,comprising filter housing 1, within which are centered two sinteredfilter discs 3, with filtering medium 2 contained between the twosintered discs. The filter is connected to an input line (not pictured)and, in a preferred embodiment, flow upward through the filter medium,such that inlet 4 is located on the lower aspect of the filter, whilethe outlet5 is located on the upper aspect of the filter.

FIG. 2 is a chart showing the composite gas chromatograms of sixdifferent samples of methane containing known concentrations of threedifferent odiferous sulfur containing hydrocarbons commonly used asodorants in natural gas. The chemicals are dimethyl sulfide at 51.4 ppm,tert-butyl mercaptan at 103 ppm, and tetrahydrothiopene at 103 ppm. Thethree tallest peaks demonstrate that the three runs coinside perfectlywith each other and down below we see the same three odorants have beenreduced to trace amounts.

Although the process of the invention may be performed in any apparatusor system capable of and suitable for performing each of the steps ofthe process as described herein, the process is preferably performedutilizing the preferred embodiments of the system as described herein.Accordingly, the terminology as used and defined in relation to oneprocess and system is equally applicable with respect to another processand system.

While the invention has been described in detail and with reference tospecific embodiments thereof, it will be apparent to one skilled in theart that various changes and modifications can be made therein withoutdeparting from the spirit and scope thereof. Thus, it is intended thatthe invention covers the modifications and variations of this inventionprovided they come within the scope of the appended claims and theirequivalents.

List of reference numbers:

-   1 Filter housing-   2 Filtering medium-   3 Sintered discs-   4 Fluid inlet-   5 Fluid outlet-   10 Fluid filter

The references recited herein are incorporated herein in their entirety,particularly as they relate to teaching the level of ordinary skill inthis art and for any disclosure necessary for the more commonunderstanding of the subject matter of the claimed invention. It will beclear to a person of ordinary skill in the art that the aboveembodiments may be altered or that insubstantial changes may be madewithout departing from the scope of the invention. Accordingly, thescope of the invention is determined by the scope of the followingclaims and their equitable equivalents.

We claim:
 1. A fluid filter for attachment to a gas or liquid line, suchfluid filter comprising a housing packed with a filtering mediumcomposition of granular particles ranging in size from about 15 mm toabout 0.001 mm and consisting of a homogeneous composition of oxides ofaluminum, antimony, barium, beryllium, bismuth, boron, cadmium, calcium,cerium, cesium, chromium, cobalt, copper, dysprosium, erbium, europium,gadolinium, gallium, germanium, hafnium, holmium, indium, iron,lanthanum, lead, lithium, lutetium, magnesium, manganese, molybdenum,neodymium, nickel, praseodymium, rhenium, rhodium, samarium, silicon,silver, strontium, titanium, vanadium, ytterbium, yttrium, zinc andzirconium, further comprising elemental gold, palladium, and platinumcollectively comprising between 0.000001% and 0.002% of the filteringmedium.
 2. The fluid filter of claim 1, further comprising an inputline, wherein the housing has a diameter three or more times larger thanthe input line diameter.
 3. The fluid filter of claim 1, wherein thehousing is three or more times longer than its own diameter.
 4. Thefluid filter of claim 1, wherein the granular particles range in sizefrom 4 mm to 0.04 mm.
 5. The fluid filter of claim 1, wherein the filtermedium composition is at least 80% oxides of copper as determined byICP-MS solution analysis of nitric acid digestions of the medium.
 6. Thefluid filter of claim 1, wherein the filtering medium is comprised of atleast 90% by total weight oxides of copper.
 7. The fluid filter of claim1, further comprising a contact temperature range from ambienttemperature up to 500° C.
 8. The fluid filter of claim 7, wherein thecontact temperature ranges from 30° C. to 300° C.
 9. The fluid filter ofclaim 1, wherein the composition of the filtering medium composition isrecyclable or regenerable.
 10. A filtering medium composition ofgranular particles ranging in size from about 15 mm down to about 0.001mm and consisting of a homogeneous composition of the oxides ofaluminum, antimony, barium, beryllium, bismuth, boron, cadmium, calcium,cerium, cesium, chromium, cobalt, copper, dysprosium, erbium, europium,gadolinium, gallium, germanium, hafnium, holmium, indium, iron,lanthanum, lead, lithium, lutetium, magnesium, manganese, molybdenum,neodymium, nickel, praseodymium, rhenium, rhodium, samarium, silicon,silver, strontium, titanium, vanadium, ytterbium, yttrium, zinc andzirconium plus elemental gold, palladium, and platinum, whereinpercentages of components are given by total weight and: oxides ofcopper comprise at least 80% of the filtering medium, non-copper oxidescomprise between 0.001% and 19.9999% of the filtering medium, andelemental gold, palladium and platinum comprise between 0.000001% and0.002% of the filtering medium.
 11. The filtering medium of claim 10,wherein: oxides of copper comprise up to 90% of the filtering medium,non-copper oxides comprise between 0.001% and 9.9999% of the filteringmedium, and elemental gold, palladium and platinum comprise between0.00001% and 0.0001% of the filtering medium.
 12. A process for removinghydrogen sulfide, sulfur containing compounds such as thiols ormercaptans, oxides of nitrogen, PFAS substances and halogens from a gasor liquid stream that lowers the concentration of these contaminants tolevels that are below the limit of detection of standard laboratoryinstrumentation by passing the gas or liquid stream through a fluidfilter, such filter comprising a filter housing with a contacttemperature ranging from about ambient to about 500C that is packed withfiltering medium composition of granular particles ranging in size fromabout 15 mm down to about 0.01 mm and consisting of a homogeneouscomposition of the oxides of aluminum, antimony, barium, beryllium,bismuth, boron, cadmium, calcium, cerium, cesium, chromium, cobalt,copper, dysprosium, erbium, europium, gadolinium, gallium, germanium,hafnium, holmium, indium, iron, lanthanum, lead, lithium, lutetium,magnesium, manganese, molybdenum, neodymium, nickel, praseodymium,rhenium, rhodium, samarium, silicon, silver, strontium, titanium,vanadium, ytterbium, yttrium, zinc and zirconium, further comprisingelemental gold, palladium, and platinum collectively comprising between0.000001% and 0.002% of the filtering medium.
 13. The process of claim12, wherein the stream flows upward through the filter.
 14. The processof claim 12, wherein the fluid filter is the fluid filter of claim 1.15. The process of claim 12, wherein the filtering medium is thefiltering medium of claim
 10. 16. The process of claim 12, wherein thestream is comprised of hydrogen, natural gas, biogas, or otherlaboratory or industrial gases or mixture of gases comprising air andspecialty high purity composite gases of the grade known as “ChemicallyPure” or “Research” that are bottled gases typically available tolaboratory and industrial customers, in pipelines, in exhaust streams,or of liquids such as organic or inorganic liquids.
 17. The process ofclaim 12, wherein hydrogen sulfide, thiols, mercaptans, other sulfurcontaining molecules, oxides of nitrogen, PFAS substances and halogensare removed from feed or exhaust fluids.